Optical imaging system

Abstract

An optical imaging system includes a first lens, a second lens, a third lens, a reflective member, and an image sensor sequentially arranged from an object side. The reflective member includes at least two reflective surfaces to change a path of light passing through the first to third lenses and incident on the reflective member at least twice.

What is claimed is: 
     
         1 . An optical imaging system comprising:
 a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a refractive power, a reflective member comprising at least two reflective surfaces configured to change a path of light passing through the first to third lenses, and an image sensor sequentially disposed along an optical axis of the optical imaging system from an object side of the optical imaging system toward an imaging surface of the image sensor,   wherein the optical imaging system has a total of three lenses having a refractive power,   a distance along the optical axis between the third lens and the reflective member is greater than a distance along the optical axis between the first lens and the second lens, and is also greater than a distance along the optical axis between the second lens and the third lens, and   0.1<LL/PL<0.4, where LL is a distance along the optical axis from an object-side surface of the first lens to an image-side surface of the third lens, and PL is a length of a path of the light in the reflective member.   
     
     
         2 . The optical imaging system of  claim 1 , wherein the reflective member is a parallelogram-shaped prism. 
     
     
         3 . The optical imaging system of  claim 1 , wherein 0.2<f1/f<0.8, where f1 is a focal length of the first lens, and f is a focal length of the optical imaging system. 
     
     
         4 . The optical imaging system of  claim 1 , wherein the object-side surface of the first lens is convex in a paraxial region thereof, and an image-side surface of the first lens is convex in a paraxial region thereof. 
     
     
         5 . The optical imaging system of  claim 1 , wherein an image-side surface of the second lens is concave in a paraxial region thereof, and the image-side surface of the third lens is concave in a paraxial region thereof. 
     
     
         6 . The optical imaging system of  claim 1 , wherein 50<v1<90 and 0≤v1−v2<56, where v1 is an Abbe number of the first lens, and v2 is an Abbe number of the second lens. 
     
     
         7 . The optical imaging system of  claim 1 , wherein −20<f2/f<−0.3, where f2 is a focal length of the second lens, and f is a focal length of the optical imaging system. 
     
     
         8 . The optical imaging system of  claim 1 , wherein −3.5<f3/f<6.2, where f3 is a focal length of the third lens, and f is a focal length of the optical imaging system. 
     
     
         9 . The optical imaging system of  claim 1 , wherein 0.80<PL/f≤0.98, where f is a focal length of the optical imaging system. 
     
     
         10 . The optical imaging system of  claim 1 , wherein an object-side surface of the second lens is concave in a paraxial region thereof, and the image-side surface of the third lens is concave in a paraxial region thereof.